half-wit vs nitwit

half-wit and nitwit both are nouns.

Word	Noun	Adjective	Verb	Adverb
half-wit	Yes	No	No	No
nitwit	Yes	No	No	No

As nouns, half-wit and nitwit are synonyms defined as:

Other synonyms of half-wit include dimwit, doofus.

half-wit (noun)	nitwit (noun)
a stupid incompetent person	a stupid incompetent person
a person of subnormal intelligence